Refactoring of USBPrinting plugin

avr_isp/ispBase.py

@@ -0,0 +1,63 @@
+"""
+General interface for Isp based AVR programmers.
+The ISP AVR programmer can load firmware into AVR chips. Which are commonly used on 3D printers.
+
+ Needs to be subclassed to support different programmers.
+ Currently only the stk500v2 subclass exists.
+"""
+__copyright__ = "Copyright (C) 2013 David Braam - Released under terms of the AGPLv3 License"
+
+from . import chipDB
+
+class IspBase():
+	"""
+	Base class for ISP based AVR programmers.
+	Functions in this class raise an IspError when something goes wrong.
+	"""
+	def programChip(self, flashData):
+		""" Program a chip with the given flash data. """
+		self.curExtAddr = -1
+		self.chip = chipDB.getChipFromDB(self.getSignature())
+		if not self.chip:
+			raise IspError("Chip with signature: " + str(self.getSignature()) + "not found")
+		self.chipErase()
+		
+		print("Flashing %i bytes" % len(flashData))
+		self.writeFlash(flashData)
+		print("Verifying %i bytes" % len(flashData))
+		self.verifyFlash(flashData)
+
+	def getSignature(self):
+		"""
+		Get the AVR signature from the chip. This is a 3 byte array which describes which chip we are connected to.
+		This is important to verify that we are programming the correct type of chip and that we use proper flash block sizes.
+		"""
+		sig = []
+		sig.append(self.sendISP([0x30, 0x00, 0x00, 0x00])[3])
+		sig.append(self.sendISP([0x30, 0x00, 0x01, 0x00])[3])
+		sig.append(self.sendISP([0x30, 0x00, 0x02, 0x00])[3])
+		return sig
+	
+	def chipErase(self):
+		"""
+		Do a full chip erase, clears all data, and lockbits.
+		"""
+		self.sendISP([0xAC, 0x80, 0x00, 0x00])
+
+	def writeFlash(self, flashData):
+		"""
+		Write the flash data, needs to be implemented in a subclass.
+		"""
+		raise IspError("Called undefined writeFlash")
+
+	def verifyFlash(self, flashData):
+		"""
+		Verify the flash data, needs to be implemented in a subclass.
+		"""
+		raise IspError("Called undefined verifyFlash")
+
+class IspError():
+	def __init__(self, value):
+		self.value = value
+	def __str__(self):
+		return repr(self.value)